The util-linux package shipped with Red Hat Linux Advanced Server contains a locally exploitable vulnerability.
The util-linux package contains a large variety of low-level system utilities that are necessary for a Linux system to function. The ‘chfn’ utility included in this package allows users to modify personal information stored in the system-wide password file, /etc/passwd. In order to modify this file, this application is installed setuid root.
Under certain conditions, a carefully crafted attack sequence can be performed to exploit a complex file locking and modification race present in this utility allowing changes to be made to /etc/passwd.
In order to successfully exploit the vulnerability and perform privilege escalation there is a need for a minimal administrator interaction. Additionally, the password file must be over 4 kilobytes, and the local attackers entry must not be in the last 4 kilobytes of the password file.
The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2002-0638 to this issue.
An interim workaround is to remove setuid flags from /usr/bin/chfn and /usr/bin/chsh. All users of Red Hat Linux should update to the errata util-linux packages which contain a patch to correct this vulnerability.
Many thanks to Michal Zalewski of Bindview for alerting us to this issue.
#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2002:137. The text
# itself is copyright (C) Red Hat, Inc.
#
include('deprecated_nasl_level.inc');
include('compat.inc');
if (description)
{
script_id(12311);
script_version("1.27");
script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/14");
script_cve_id("CVE-2002-0638");
script_xref(name:"CERT", value:"405955");
script_xref(name:"RHSA", value:"2002:137");
script_name(english:"RHEL 2.1 : util-linux (RHSA-2002:137)");
script_summary(english:"Checks the rpm output for the updated package");
script_set_attribute(
attribute:"synopsis",
value:"The remote Red Hat host is missing a security update."
);
script_set_attribute(
attribute:"description",
value:
"The util-linux package shipped with Red Hat Linux Advanced Server
contains a locally exploitable vulnerability.
The util-linux package contains a large variety of low-level system
utilities that are necessary for a Linux system to function. The
'chfn' utility included in this package allows users to modify
personal information stored in the system-wide password file,
/etc/passwd. In order to modify this file, this application is
installed setuid root.
Under certain conditions, a carefully crafted attack sequence can be
performed to exploit a complex file locking and modification race
present in this utility allowing changes to be made to /etc/passwd.
In order to successfully exploit the vulnerability and perform
privilege escalation there is a need for a minimal administrator
interaction. Additionally, the password file must be over 4 kilobytes,
and the local attackers entry must not be in the last 4 kilobytes of
the password file.
The Common Vulnerabilities and Exposures project (cve.mitre.org) has
assigned the name CVE-2002-0638 to this issue.
An interim workaround is to remove setuid flags from /usr/bin/chfn and
/usr/bin/chsh. All users of Red Hat Linux should update to the errata
util-linux packages which contain a patch to correct this
vulnerability.
Many thanks to Michal Zalewski of Bindview for alerting us to this
issue."
);
script_set_attribute(
attribute:"see_also",
value:"https://access.redhat.com/security/cve/cve-2002-0638"
);
# http://razor.bindview.com/publish/advisories/adv_chfn.html
script_set_attribute(
attribute:"see_also",
value:"http://www.nessus.org/u?9606bdfd"
);
script_set_attribute(
attribute:"see_also",
value:"https://access.redhat.com/errata/RHSA-2002:137"
);
script_set_attribute(
attribute:"solution",
value:"Update the affected util-linux package."
);
script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:N/C:C/I:C/A:C");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:util-linux");
script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:2.1");
script_set_attribute(attribute:"vuln_publication_date", value:"2002/08/12");
script_set_attribute(attribute:"patch_publication_date", value:"2002/07/29");
script_set_attribute(attribute:"plugin_publication_date", value:"2004/07/06");
script_set_attribute(attribute:"generated_plugin", value:"current");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_copyright(english:"This script is Copyright (C) 2004-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");
script_family(english:"Red Hat Local Security Checks");
script_dependencies("ssh_get_info.nasl");
script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");
exit(0);
}
include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
include("rpm.inc");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Red Hat" >!< release) audit(AUDIT_OS_NOT, "Red Hat");
os_ver = pregmatch(pattern: "Red Hat Enterprise Linux.*release ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Red Hat");
os_ver = os_ver[1];
if (! preg(pattern:"^2\.1([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Red Hat 2.1", "Red Hat " + os_ver);
if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$" && "s390" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Red Hat", cpu);
if (cpu !~ "^i[3-6]86$") audit(AUDIT_ARCH_NOT, "i386", cpu);
yum_updateinfo = get_kb_item("Host/RedHat/yum-updateinfo");
if (!empty_or_null(yum_updateinfo))
{
rhsa = "RHSA-2002:137";
yum_report = redhat_generate_yum_updateinfo_report(rhsa:rhsa);
if (!empty_or_null(yum_report))
{
security_report_v4(
port : 0,
severity : SECURITY_WARNING,
extra : yum_report
);
exit(0);
}
else
{
audit_message = "affected by Red Hat security advisory " + rhsa;
audit(AUDIT_OS_NOT, audit_message);
}
}
else
{
flag = 0;
if (rpm_check(release:"RHEL2.1", cpu:"i386", reference:"util-linux-2.11f-17.7.2")) flag++;
if (flag)
{
security_report_v4(
port : 0,
severity : SECURITY_WARNING,
extra : rpm_report_get() + redhat_report_package_caveat()
);
exit(0);
}
else
{
tested = pkg_tests_get();
if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
else audit(AUDIT_PACKAGE_NOT_INSTALLED, "util-linux");
}
}
Vendor | Product | Version | CPE |
---|---|---|---|
redhat | enterprise_linux | util-linux | p-cpe:/a:redhat:enterprise_linux:util-linux |
redhat | enterprise_linux | 2.1 | cpe:/o:redhat:enterprise_linux:2.1 |